Final answer:
Cesium (Cs) is the element found in salt replacements from the provided list. It is used as a salt substitute in the form of cesium chloride. Cesium is part of the alkali metals and is more rarely found in nature compared to sodium and potassium.
Step-by-step explanation:
Among Al, Au, Br, Ca, Cs, F, H, He, Hg, I, K, Mg, Na, O, P, S, and Si, Cs or cesium is found in salt replacements. Cesium chloride is commonly used as a salt substitute, particularly for individuals who need a low sodium diet. Cesium is one of the alkali metals, which are characterized by their highly reactive nature and are commonly found in various compounds rather than in a pure elemental form.
While sodium and potassium from Group 1 elements are found abundantly in nature and widely used in applications such as table salt (sodium chloride) and potassium bromide, cesium is much rarer. However, it is still used in certain applications due to its properties and can be found in salt substitute products, demonstrating a clear connection between the characteristics of these alkali metals and their uses in everyday products.